During the past year the investigations carried out within this project led to results of some interest in two areas. Firstly, the serum amyloid A level was found to be a close monitor of cancer dissemination and of the response to therapy of patients with metastatic neoplasia. SAA levels above 400 ng/ml were found in 97% of 289 patients with solid tumors with distant metastases, in patients with acute and chronic myelocytic leukemia and patients with advanced lymphoma. They were lower than 400 ng/ml in 250 out of 270 patients with solid malignant tumors with localized and regional diseease free of inflammatory processes. Among 20 patients from the latter group with SAA level higher than 400 ng/ml, 16 developed metastases within 214 days from the initial determination. The SAA level decreased in patients who responded to chemotherapy. A statistically significant correlation (p is less than 0.01) was established between the level of SAA and the size of measurable tumors. Secondly, it was established that among various subpopulations of peripheral human leukocytes the polymorphonuclear leukocytes or granulocytes are capable of synthesizing an AA antigenically related material designated granulocyte amyloid A (GAA). It was found that granulocytes, separated from 50 ml heparinized blood from 5 patients with high SAA levels, were able to incorporate 14C leucine (1 microcurie/ml McCoy medium free of leucine) in the de novo synthesized GAA detected in the solubilized granulocyte pellet and in their supernatant with the help of a double radioimmunoassay. The amount of intracellular 14C GAA was found to rise from 155 to 2200 cpm/4 x 10 to the 6th power cells over a period of 20 hours, then to decrease, while the extracellular 14C GAA increased proportionally with the percentage of dead leukocytes. Puromycin and cycloheximide significantly inhibited the synthesis of 14C GAA, vincristine and colchicine (antitubulin drugs) primarily blocked GAA release from the cells, while hydrocortisone increased its release and endotoxins in small doses increased its rate of synthesis. Preliminary data indicate that GAA is a protein of intermediate molecular weight (approximately 100,000 daltons). During the coming year the factors governing GAA synthesis and release will be analyzed, attempts will be made to isolate, purify and characterize (Text Truncated - Exceeds Capacity)